1. Field of the Invention
This invention relates to thin wall metal beverage cans, and in particular to aluminum beverage cans having a threaded neck portion for receiving a threaded closure cap to seal the contents of the container.
2. Description of the Prior Art
Aluminum cans are now widely used in the packaging of beer, soft drinks, etc. and these are typically adapted to be closed with relatively flat lids or ends. Although the standard aluminum cans offer a number of advantages for the beverage suppliers, such as low cost, excellent barrier properties, recyclability, etc., there is at present a significant interest in reclosable/resealable cans for certain market segments. As an example, beverages supplied at gas stations or convenience stores, are preferably supplied in a reclosable (and preferably resealable) format. As a result, cans are rarely the container of choice at these outlets.
There have been many attempts to design a reclosable can, but so far, market penetration has been very limited. Generally the added cost of such modifications means that the package can only be considered for what are generally referred to as “high-end” beverages. For instance, a type of bottle can has recently been developed for use in the sale of premium beers. Such cans have, however, not penetrated the low cost soft drink market.
In order to be successful, a reclosable can must offer a number of benefits. It must, for instance, provide a shelf life comparable or better than that of the PET bottles. The closure must be easy to use and, ideally, after closing the seal should prevent any further loss of carbonation. Finally, the cost of the package must be acceptable in being no more than only slightly higher than current can costs.
One attempt to provide a can which may be reclosed and resealed is shown in Roth U.S. Pat. No. 4,452,368 issued Jun. 5, 1984.This design has a central plug which is pushed into a pour opening.
Another form of closable beverage can is shown in laid open German Application DE 198 02 953 A1, published Jul. 29, 1999.This design includes punching a hole in the center of the top of the can and fitting into this hole a resealable closure system with a screw cap.
PCT Publication No. WO 99/10242 published Mar. 4, 1999 shows yet another form of resealable can closure making use of a screw cap.
Dickhoff et al. U.S. Pat. No. 6,010,026 issued Jan. 4, 2000 shows a reclosable can that can be produced in a variety of different shapes, all with a threaded top for receiving a threaded closure cap.
It is an object of the present invention to provide an improved form of reclosable and resealable metal can design which functions well while being easy and inexpensive to produce.